There has been known an organic electroluminescence device (hereinafter, occasionally referred to as an “organic EL device”) that includes an emitting unit (in which an emitting layer is included) between an anode and a cathode and emits light using exciton energy generated by a recombination of holes and electrons that have been injected into the emitting layer.
A phosphorescent organic EL device using a phosphorescent dopant material as a luminescent material has been known as the organic EL device. The phosphorescent organic EL device can achieve a high luminous efficiency by using a singlet state and a triplet state of excited states of the phosphorescent dopant material. The reason is presumed as follows. When holes and electrons are recombined in the emitting layer, it is presumed that singlet excitons and triplet excitons are produced at a rate of 1:3 due to difference in spin multiplicity. Accordingly, luminous efficiency of the device using a phosphorescent material can reach three to four times as much as that of the device using only a fluorescent material.
Patent Literature 1 describes that a compound in which a nitrogen-containing heterocyclic group is bonded to an arylcarbazoyl group or a carbazoyl alkylene group is suitable to a phosphorescent host material usable in combination with a phosphorescent dopant material. An organic EL device driven at a low voltage and having a high color purity is obtainable by using the phosphorescent dopant material and this compound in the emitting layer.